Eur. Phys. J. B (2017) 90: 20
https://doi.org/10.1140/epjb/e2016-70619-y

Regular Article

Output response identification in a multistable system for piezoelectric energy harvesting

¹ Department of Mechanical Engineering, University of Bath, Bath BA2 7AY, UK
² Mechanical Engineering Department, American University in Cairo, AUC Avenue, P.O. Box 74, 11835 New Cairo, Egypt
³ Faculty of Mechanical Engineering, Lublin University of Technology, Nadbystrzycka 36, 20-618 Lublin, Poland
⁴ Department of Process Control, AGH University of Science and Technology, Mickiewicz Alley 30, 30-059 Krakow, Poland
⁵ Department of Robotics and Mechatronics, AGH University of Science and Technology, Mickiewicz Alley 30, 30-059 Krakow, Poland

^a e-mail: g.litak@pollub.pl

Received: 17 October 2016
Received in final form: 6 December 2016
Published online: 25 January 2017

Abstract

In this paper we examine in detail the multiple responses of a novel vibrational energy harvester composed of a vertical bistable beam whose complex non-linear behavior is tuned via magnetic interaction. The beam was excited horizontally by a harmonic inertial force while mechanical vibrational energy is converted to electrical power through a piezoelectric element. The bistable laminate beam coupled to the piezoelectric transducer showed a variety of complex responses in terms of the beam displacement and harvested power output. The range of vibration patterns in this non-linear system included single-well oscillations and snap-through vibrations of periodic and chaotic character. Harvested power was found to be strongly dependent on the vibration pattern with nonlinearities providing a broadband response for energy harvesting. Wavelet analysis of measured voltage, displacement and velocity time histories indicated the presence of a variety of nonlinear periodic and also chaotic phenomena. To measure the complexity of response time series we applied phase portraits and determine stroboscopic points and multiscale entropy. It is demonstrated that by changing parameters such as the magnetic interaction, the characteristics of the bistable laminate harvester, such as the natural frequency, bandwidth, vibration response and peak power can be readily tailored for harvesting applications.